Plasma processing system, electron beam generator, and method of fabricating semiconductor device

ABSTRACT

A chamber has an upper housing and a lower housing and receives a reaction gas. A first plasma source includes electron beam sources providing electron beams into the upper housing to generate an upper plasma. A second plasma source includes holes generating a lower plasma within the holes connecting the upper housing and the lower housing. Radicals of the upper plasma, radicals of the lower plasma, and ions of the lower plasma are provided, through the holes, to the lower housing so that the lower housing has radicals and ions at a predetermined ratio of the ions to the radicals in concentration. The second plasma source divides the chamber into the upper housing and the lower housing. A wafer chuck is positioned in the lower housing to receive a wafer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to Korean PatentApplication No. 10-2017-0137423, filed on Oct. 23, 2017, in the KoreanIntellectual Property Office, the disclosure of which is incorporated byreference herein in its entirety.

TECHNICAL FIELD

The present inventive concept relates to a plasma processing system, anelectron beam generator and a method of fabricating a semiconductordevice.

DISCUSSION OF RELATED ART

Semiconductor devices are fabricated by using various unit processes.The unit processes include a deposition process, a lithography process,and an etching process. The deposition process and the etching processmay be performed using plasma. The plasma is used to treat a substrate.

SUMMARY

According to an exemplary embodiment of the present inventive concept, aplasma processing system is provided as follows. A chamber has an upperhousing and a lower housing and receives a reaction gas. A first plasmasource includes electron beam sources providing electron beams into theupper housing to generate an upper plasma. A second plasma sourceincludes holes generating a lower plasma within the holes connecting theupper housing and the lower housing. Radicals of the upper plasma,radicals of the lower plasma, and ions of the lower plasma are provided,through the holes, to the lower housing so that the lower housing hasradicals and ions at a predetermined ratio of the ions to the radicalsin concentration. The second plasma source divides the chamber into theupper housing and the lower housing. A wafer chuck is positioned in thelower housing to receive a wafer.

According to an exemplary embodiment of the present inventive concept,an electron beam generator generating a plurality of electron beams isprovided as follows. A plurality of electron beam sources are disposedat a first radius from a center of the electron beam source and at asecond radius from the center, the second radius being greater than thefirst radius. Each of the plurality of electron beam sources generatingone of the plurality of electron beams includes a source housing havinga hollow inside and an opening and receiving a source gas, an RF powergenerating a source plasma from the source gas in the hollow inside ofthe source housing, the source plasma including a plurality ofelectrons, and a source electrode having an aperture, the sourceelectrode being configured to cause to extract, through the opening ofthe source housing, the plurality of electrons from the source plasma ofthe source housing and accelerate the plurality of electrons extractedfrom the source plasma to travel away from the opening of the sourcehousing.

According to an exemplary embodiment of the present inventive concept, amethod of fabricating a semiconductor device on a wafer is provided asfollows. An upper plasma using an electron beam is generated. Aplurality of lower plasma are generated using an RF power. The pluralityof lower plasmas are spaced apart from each other. A reaction plasma isformed on the wafer from the upper plasma and the plurality of lowerplasmas. The reaction plasma has radicals and ions in a predeterminedratio of the ions to the radicals in concentration, The forming of thereaction plasma includes providing radicals of the upper plasma andradicals of the plurality of lower plasmas to the reaction plasma,providing ions of the plurality of lower plasmas to the reaction plasma,and blocking ions of the upper plasma from being provided to thereaction plasma.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present inventive concept will becomemore apparent by describing in detail exemplary embodiments thereof withreference to the accompanying drawings of which:

FIG. 1 is a diagram schematically illustrating a plasma processingsystem according to an exemplary embodiment of the present inventiveconcept;

FIGS. 2 to 6 are diagrams illustrating exemplary electron beam sourcesof FIG. 1 according to the present inventive concept;

FIGS. 7 and 8 are plan views illustrating an exemplary confinementelectrode of FIG. 1 according to the present inventive concept;

FIGS. 9 and 10 are diagrams illustrating a plasma processing systemaccording to an exemplary embodiment of the present inventive concept;

FIG. 11 is a plan view illustrating an exemplary magnetic coil of FIG. 9according to the present inventive concept;

FIGS. 12 and 13 are plan views showing a change in open state of cathodeholes, which is caused by rotation of a shutter plate of FIGS. 9 and 10,according to an exemplary embodiment of the present inventive concept;

FIG. 14 is a flow chart illustrating a method of fabricating asemiconductor device, according to an exemplary embodiment of thepresent inventive concept; and

FIG. 15 is a diagram illustrating a semiconductor fabricating systemincluding the plasma processing system of FIG. 1, according to anexemplary embodiment of the present inventive concept.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present inventive concept will be describedbelow in detail with reference to the accompanying drawings. However,the inventive concept may be embodied in different forms and should notbe construed as limited to the embodiments set forth herein. In thedrawings, the thickness of elements, the size of the elements andregions where the elements are positioned may be exaggerated forclarity. Like reference numerals may refer to the like elementsthroughout the specification and drawings.

FIG. 1 is a diagram schematically illustrating a plasma processingsystem 100 according to an exemplary embodiment of the present inventiveconcept.

Referring to FIG. 1, the plasma processing system 100 may generateplasma using an electron beam. The plasma processing system 100 mayinclude a chamber 10, a gas supplying part 20, an electrostatic chuck30, a hollow cathode 40, electron beam sources 50, and a confinementelectrode 60. A substrate W may be disposed in the chamber 10. The gassupplying part 20 may supply a reaction gas 22 into the chamber 10. Thesubstrate W may be loaded on the electrostatic chuck 30. The hollowcathode 40 may generate a lower plasma 104 within the hollow cathode 40.The following patent document Korean Patent Application No.10-2017-0137420 and 10-2017-0137421 are hereby incorporated by referenceregarding the configuration of the hollow cathode 40. In someembodiments, physical properties (e.g., energy or intensity) of thelower plasma 104 may be changed to control a ratio of ions to radicalsin concentration, which are produced from the reaction gas 22, in areaction plasma 106. The electron beam sources 50 may provide electronbeams 52 directed to the hollow cathode 40, thereby generating an upperplasma 102 from the reaction gas 22. The confinement electrode 60 mayconcentrate the electron beams 52 in the upper plasma 102 so that theelectron beams 52 may be guided toward the hollow cathode 40. Withoutthe confinement electrode 60, electrons of the electron beams 52 may bescattered away toward walls of the chamber 10. The confinement electrode60 may serve to guide or direct the electrons scattered away toward thehollow cathode 40 so that the electron beams 52 may have more collisionswith the reaction gas 22. Hereinafter, the upper plasma 102 and thelower plasma 104 will be described in more detail below.

The chamber 10 may provide an isolated space for the substrate W. Thechamber 10 may be configured to have a pressure of about 10⁻³ Torr. Thechamber 10 may include a lower housing 10-LH and an upper housing 10-UH.If the lower housing 10-LH is separated from the upper housing 10-UH,the substrate W may be loaded on the electrostatic chuck 30 by a robotarm (not shown). Thereafter, the upper housing 10-UH and the lowerhousing 10-LH may be combined to each other to seal the chamber 10.

The gas supplying part 20 may be connected to the chamber 10. The gassupplying part 20 may supply the reaction gas 22 into a region of thechamber 10 located on the hollow cathode 40. For example, the reactiongas 22 may be provided into the upper housing 10-LH and the hollowcathode 40 through the upper housing 10-LH. The reaction gas 22 maycontain an etching gas (e.g., NF₃, CF₄, HBr, HCl, CCl₄, SF₆, HF, CH₃, orCH₄), an inert gas (e.g., Ar or He), or a purge gas (e.g., N₂). Incertain embodiments, the reaction gas 22 may contain a deposition gas(e.g., SiH₄ or NH₃).

The electrostatic chuck 30 may be placed in the lower housing 10-LH ofthe chamber 10. The electrostatic chuck 30 may hold the substrate Wusing an electrostatic force. Although not shown, the electrostaticchuck 30 may be coupled to a plasma power source so that ions entering asheath formed on the wafer are accelerated toward the wafer. Forexample, the plasma power source may include a direct current (DC) poweror an RF power.

The hollow cathode 40 may be disposed between the electrostatic chuck 30and the electron beam sources 50. The hollow cathode 40 may be parallelto the electrostatic chuck 30 and the substrate W. The hollow cathode 40may include a dielectric plate 42 and electrodes 44. In an exemplaryembodiment, the dielectric plate 42 may be formed of an insulatingmaterial including ceramics such as Al₂O₃. The dielectric plate 42 maybe a disk. The dielectric plate 42 may have cathode holes 41. In anexemplary embodiment, the cathode holes 41 may range from about 10 um toabout 2 mm in diameter. The cathode holes 41 may allow the reaction gas22 to be supplied onto the substrate W. For example, each of the cathodeholes 41 may have a diameter ranging from about 10 um to about 2 mm. Theelectrodes 44 may be provided in the dielectric plate 42. In someembodiments, the electrodes 44 may include lower electrodes 43 and upperelectrodes 45. The lower plasma 104 may be generated from the reactiongas 22 in the cathode holes 41 using RF power supplied to the electrodes44. A first power supplying unit 32 may provide the RF power to thereaction gas 22 confined within the cathode holes 41 through the lowerelectrodes 43 and the upper electrodes 45. The lower electrodes 43 maybe biased with a ground, and the upper electrodes 45 may be coupled tothe first power supplying unit 32. The RF power may have a frequencyranging from about 1 KHz to about 100 MHz. The energy of the lowerplasma 104 may be dependent on the intensity of the RF power. If theenergy of the lower plasma 104 is increased, radicals of the reactiongas 22 (e.g., F, N, H, Br, Cl, or C) generated within the cathode holes41 may be decreased in concentration, and ions of the reaction gas 22(e.g., F⁺, NF²⁺, NF2⁺, H⁺, Br⁺, Cl⁺ or C⁺) generated within the cathodeholes 41 may be increased in concentration. As the ratio of the ionsover the radicals in concentration increases, the etching caused by theions and the radicals may have more directionality and thus an etchingdepth of the substrate W may be increased. For the deposition, adeposition rate of a thin film to be deposited on the substrate W maydepend on a ratio of the ions to the radicals in concentration.

The electron beam sources 50 may be arranged on the chamber 10. Forexample, the electron beam sources 50 may be provided in upper ports 12,respectively, of the chamber 10. The electron beam sources 50 may bearranged in a direction parallel to the dielectric plate 42. Theelectron beam sources 50 may provide the electron beams 52 in adirection perpendicular to the dielectric plate 42 and the electrostaticchuck 30. The electron beams 52 may be directed in the same direction asthe cathode holes 41. The electron beams 52 may generate the upperplasma 102 from the reaction gas 22 on the dielectric plate 42. Theenergy of the upper plasma 102 may be dependent on the energy intensityof the electron beams 52.

The chamber 10 may be divided into the upper housing 10-UH and the lowerhousing 10-LH by the hollow cathode 40. The upper housing 10-UH maycontain the upper plasma 102 having ions at a first ion concentrationand radicals at a first radical concentration. The upper plasma 102 maybe generated from the reaction gas 22 supplied into the upper housing10-UH. The hollow cathode 40 may contain in the cathode holes 41 thelower plasma 104 having ions at a second ion concentration and radicalsat a second radical concentration. The lower plasma 104 may be generatedfrom the reaction gas 22 supplied into the cathode holes 41 through theupper housing 10-UH. The lower housing 10-UH may contain ions comingfrom the cathode holes 41 of the hollow cathode 40 and radicals comingfrom the cathode holes 41. The ions coming from the cathode holes 41 maybe originated from the lower plasma 104. The ions of the upper plasma102 may be repelled back into the upper plasma 102 due to a DC biasformed on the hollow cathode 40 by the first power supplying unit 32. Inother words, the DC bias formed on the hollow cathode 40 may block theions of the upper plasma 102 from being provided to the lower housing10-LH. The radicals of the upper plasma may pass through the cathodeholes 41. The ions of the lower plasma 104 and the radicals of the lowerplasma 104 may be provided into the lower housing 10-LH. Accordingly,the lower housing 10-LH may contain radicals originated from both theupper plasma 102 and the lower plasma 104 and ions originated from thelower plasma 104 only. The concentration of the radicals in the lowerhousing 10-LH may be determined by the first radical concentration ofthe upper plasma 102 and the second radical concentration of thereaction plasma 106. The concentration of the ions in the lower housing10-LH may be determined only by the second ion concentration of thelower plasma 104. Some ions of the upper plasma 102 may have a kineticenergy sufficient to overcome the DC bias formed on hollow cathode 40 bythe first power supplying unit 32 so that they may pass through thecathode holes 41 to be provided into the lower housing 10-LH. However,the amount of the ions of the upper plasma 102 with such high kineticenergy may be very small compared to the second ion concentration of thelower plasma 104 so that it may be ignored in controlling the ratio ofthe ions to the radicals in concentration of the lower housing 10-LH toa predetermined ratio of the ions to the radicals in the lower housing10-LH.

The lower housing 10-LH may contain a reaction plasma 106 having ions ata third ion concentration determined only by the second ionconcentration of the lower plasma 104 and radicals at a third radicalconcentration determined by the first radical concentration of the upperplasma 102 and the second radical concentration of the lower plasma 104.The third ion concentration of the reaction plasma 106 may be alsodetermined by a number of the cathode holes 41 or a width of each of thecathode holes 41. The third radical concentration of the reaction plasma106 may be also determined by the number of the cathode holes 41 or thewidth of each of the cathode holes 41. In an exemplary embodiment, theratio of the ions to the radicals in the reaction plasma 106 may becontrolled by the RF power of the first power supplying unit 32, whichmay generate the lower plasma 104 in the cathode holes 41. For example,the RF power of the first power supplying unit 32 may be controlled sothat the reaction plasma 106 may have a predetermined ratio of the ionsto the radicals in the reaction plasma 106.

A first plasma source may include the electron beam sources 50. Thehollow cathode 40 and the first power supplying unit 32 may be referredto as a second plasma source. The first power supplying unit 32 may bereferred to as a first RF power. The cathode holes 41 may be referred toas a plurality of holes.

In an exemplary embodiment, the first power supplying unit 32 (or thefirst RF power) may be coupled to the upper electrodes 45 and a groundvoltage may be coupled to the lower electrodes 43 so that the dielectricplate 42 has a positive DC bias to block the ions of the upper plasma102 from being provided into the lower housing 10-LH through the cathodeholes 41. In other words, the reaction plasma 106 need not include theions of the upper plasma 102.

In an exemplary embodiment, the first power supplying unit 32 mayprovide an RF power of which frequency ranges from about 1 KHz to about100 MHz.

In an exemplary embodiment, the electrostatic chuck 30 may have a centerCNT that is vertically aligned with a center of an electron beamgenerator including the electron beam sources 50 having a plurality offirst electron beam sources 50A and a plurality of second electron beamsources 50B. The first electron beam sources 50A may be positionedwithin a perimeter of the wafer W; and the second electron beam sources50B may overlap the perimeter of the wafer W. The present inventiveconcept is not limited thereto. For example, the second electron beamsources 50B may be positioned outside the perimeter of the wafer W.

FIG. 2 illustrates an exemplary electron beam source of FIG. 1 accordingto the present inventive concept.

Referring to FIG. 2, an electron beam source 50 a may include an RFpower supplying unit 51, a source housing 54, a first grid electrode 56and a second grid electrode 57. The source housing 54 may define ahollow inside and may have an opening 54-O. The RF power supplying unit51 may be configured to provide a source RF power to the source housing54. The source RF power may have a frequency ranging from about 1 KHz toabout 1 MHz. The source RF power may generate a source plasma 96 havingelectrons e⁻ from a first source gas 92 and a second source gas 94, inthe source housing 54. The first source gas 92 may include helium (He).The second source gas 94 may include argon (Ar). The source housing 54may have a vertical partition wall 55 that is erected vertically from aninside surface of the source housing 54 toward the opening 54-O of thesource housing 54. The vertical partition wall 55 may divide an internalspace of the source housing 54 in a lateral direction into a firstdivided internal space 54-1 and a second divided internal space 54-2.The first source gas 92 may be provided in the first divided internalspace 54-1. The second source gas 94 may be provided in the seconddivided internal space 54-2. The first grid electrode 56 may be providedbelow the source housing 54. The second grid electrode 57 may beprovided below the first grid electrode 56. The first grid electrode 56may be interposed between the source housing 54 and the second gridelectrode 57. The first grid electrode 56 may be biased with a positivevoltage so that the first grid electrode 56 may serve to extract theelectrons e⁻ from the source plasma 96 in the hollow inside of thesource housing 54 through the opening 54-O. The second grid electrode 57may be biased with a negative voltage so that the second grid electrode57 may accelerate the electrons e⁻ extracted from the hollow inside ofthe source housing 54 through a first aperture 56-A of the first gridelectrode 56 to form the electron beam 52. The electron beam 52 may beprovided into the chamber 10 of FIG. 1 through a second aperture 57-A ofthe second grid electrode 57. The first grid electrode 56 may bereferred to as a first source electrode; and the second grid electrode57 may be referred to as a second source electrode. The RF powersupplying unit 51 may be referred to as a second RF power.

In an exemplary embodiment, the opening 54-O of the source housing 54,the first aperture 56-A of the first grid electrode 56 and the secondaperture 57-A of the second grid electrode 57 may be aligned along atraveling direction of the electron beam 52 so that the electrons of theelectron beam 52 may pass from the source plasma 96 in the hollow insideof the source housing 54 to the upper housing 10-UH of the chamber 10.

In an exemplary embodiment, the first source electrode may be biasedwith a negative voltage to extract the electrons from the source plasma96 in the hollow inside of the source housing 54 through the opening54-O of the source housing 54 and the second source electrode may bebiased with a positive voltage to accelerate the electrons passingthrough the first aperture 56-A of the first source grid electrode tooutput the electron beam through the second aperture 57-A to the upperhousing 10-UH of the chamber 10.

In an exemplary embodiment, a source electrode may include the firstgrid electrode 56 with the first aperture 56-A and the second gridelectrode 57 with the second aperture 57-A.

FIG. 3 illustrates an exemplary electron beam source of FIG. 1 accordingto the present inventive concept.

Referring to FIG. 3, an electron beam source 50 b may include the sourcehousing 54 with a horizontal partition wall 58. The RF power supplyingunit 51, the first grid electrode 56 and second grid electrode 57 may beconfigured to have the same features as those of the previous exampledescribed with reference to FIG. 2. The horizontal partition wall 58 maydivide the internal space of the source housing 54 in a verticaldirection into a first divided internal space 54-1′ and a second dividedinternal space 54-2′. The first divided internal space 54-1′ may be anupper region of the source housing 54. The second divided internal space54-2′ may be a lower region of the source housing 54. The first sourcegas 92 may be provided into the first divided internal space 54-1′. Thesecond source gas 94 may be provided into the second divided internalspace 54-2′. The horizontal partition wall 58 may have a partition wallhole 58 a. If the first source gas 92 passes through the partition wallhole 58 a, it may be mixed with the second source gas 94 in the seconddivided internal space 54-2′. The source RF power may generate thesource plasma 96 having the electrons e⁻ from the first source gas 92and the second source gas 94.

In an exemplary embodiment, the horizontal partition wall 58 may havethe partition wall hole 58 a. The partition wall may be disposedhorizontally in the hollow inside of the source housing 54 with thepartition wall hole 58 a facing the opening 54-O of the source housing54.

FIG. 4 illustrates an exemplary electron beam source of FIG. 1 accordingto the present inventive concept.

Referring to FIG. 4, an electron beam source 50 c may further include athird grid electrode 59 other than the first grid electrode 56 and thesecond grid electrode 57 described with reference to FIG. 2 or 3. The RFpower supplying unit 51, the first grid electrode 56 and the second gridelectrode 57 may be configured to have the same features as those of theprevious example described with reference to FIG. 2 or FIG. 3. The thirdgrid electrode 59 may be provided below the second grid electrode 57 andmay serve to further accelerate the electron beam 52. The velocity ofthe electron beam 52 may be determined by a magnitude of an accelerationvoltage in the third grid electrode 59. Although not shown, the electronbeam source 50 c may further include fourth to n-th grid electrodes. Thesource housing 54 may be provided on the first grid electrode 56, asshown in FIG. 2 or 3. The source plasma 96 having the electrons e⁻ maybe generated in the source housing 54 b. Unlike FIG. 2 or 3, the sourcehousing 54 need not have a partition dividing the source housing 54vertically or laterally.

FIG. 5 illustrates an exemplary electron beam source of FIG. 1 accordingto the present inventive concept.

Referring to FIG. 5, an electron beam source 50 d may include a blockelectrode 57 a including a first sub-electrode 57 a-1 and a secondsub-electrode 57 a-2. The RF power supplying unit 51, the source housing54, and the first grid electrode 56 may be configured to have the samefeatures as those of the previous examples described with reference toFIGS. 2 to 4. The block electrode 57 a may be provided below the firstgrid electrode 56. The block electrode 57 a may be provided at aposition of the second grid electrode 57 of FIG. 2 and may be separatedfrom each other. The block electrode 57 a may be referred to as a secondgrid electrode or a second source electrode. The block electrode 57 amay be individually biased. For example, the second sub-electrode 57 a-2may be grounded, and the first sub-electrode 57 a-1 may be biased with apositive voltage. The block electrode 57 a may be configured to deflectthe electron beam 52.

FIG. 6 illustrates an exemplary electron beam source of FIG. 1 accordingto the present inventive concept.

Referring to FIG. 6, an electron beam source 50 e may include a sourcecoil 80. The RF power supplying unit 51, the source housing 54, thefirst grid electrode 56 and the second grid electrode 57 may beconfigured to have the same features as those of the previous examplesdescribed with reference to FIGS. 2 to 4. The source coil 80 may beprovided on an outer circumference surface of the source housing 54. Thesource coil 80 may separate the electrons e⁻ from the source plasma 96in the source housing 54.

Referring back to FIG. 1, the confinement electrode 60 may be providedon an inner side surface of the chamber 10 and between the electron beamsources 50 and the hollow cathode 40. A voltage supplying unit 34 mayapply a bias voltage V to the confinement electrode 60. The bias voltageV may electrically control the upper plasma 102 or the electron beams52, which are adjacent to the confinement electrode 60. The bias voltageV may be a DC voltage. The bias voltage V may range from about −1 V toabout 1 KV. If the bias voltage V is negative, the electron beams 52adjacent to the inner side surface of the chamber 10 may be deflected ina direction away from the confinement electrode 60. If the bias voltageV is positive, the upper plasma 102 may move away from the confinementelectrode 60 and the electron beams 52 may be deflected in a directiontoward the confinement electrode 60.

FIG. 7 illustrates an exemplary confinement electrode 60 of FIG. 1according to the present inventive concept.

Referring to FIGS. 1 and 7, the confinement electrode 60 may be aring-shaped structure extending along the inner side surface of thechamber 10. The confinement electrode 60 may have a circular,rectangular, or ring-shaped section. When viewed in a plan view, theelectron beam sources 50 may be provided within the confinementelectrode 60. The confinement electrode 60 may serve to concentrate theelectron beams 52 within a center region 14 of the chamber 10 or thehollow cathode 40 using the bias voltage V. The electron beams 52 nearan edge region 16 of the chamber 10 may be deflected toward the centerregion 14 by the bias voltage V applied to the confinement electrode 60.

Referring to FIGS. 1 and 8, the electron beam sources 50 may include aplurality of first electron beam sources 50A and a plurality of secondelectron beam sources 50B. The first electron beam sources 50A may bedisposed within a perimeter W-PM of the wafer W if placed on theelectrostatic chuck 30. The electrostatic chuck 30 may be referred to asa wafer chuck. The second electron beam sources 50B may overlap theperimeter W-PM of the wafer W if placed on the electrostatic chuck 30 ormay be disposed outside of the perimeter W-PM of the wafer W if placedon the electrostatic chuck 30. A number of the first electron beamsources 50A may be smaller than a number of the second electron beamsources 50B. The first electron beam sources 50A are equally positionedfrom a center CNT of the electrostatic chuck 30 (or a center of thewafer chuck).

In an exemplary embodiment, an electron beam generator may include theelectron beam sources 50 disposed at a first radius r1 from a center ofthe electron beam generator, and at a second radius r2 from the centerof the electron beam generator, the second radius r2 being greater thanthe first radius r1. The center of the electron beam generator maycoincide with the center CNT of the wafer chuck. The electron beamsources 50 having the first electron beam sources 50A and the secondelectron beam sources 50B that are concentrically arranged may bereferred to as the electron beam generator. The first electron beamsources 50 and the second electron beam sources 50 may be concentricallyarranged around the center CNT of the wafer chuck 30 or the center ofthe electron beam generator.

FIG. 8 illustrates an exemplary confinement electrode 60 of FIG. 1according to the present inventive concept.

Referring to FIGS. 1 and 8, the confinement electrode 60 a may includeplurality of electrode sectors 62. The electrode sectors 62 may bearranged along the inner side surface of the chamber 10 to form acircular shape. The confinement electrode 60 a may include eightelectrode sectors 62, for example, as shown in FIG. 8. Each of theelectrode sectors 62 may have an azimuth angle θ of about 45°. Theelectrode sectors 62 may be connected to the voltage supplying unit 34.The voltage supplying unit 34 may independently supply the bias voltageV to each of the electrode sectors 62. The electron beams 52 each may beindividually controlled in at least one of the electrode sectors 62.Each electrode sector may be separated at a unit of the azimuth angle θ.

FIGS. 9 and 10 illustrate a plasma processing system according to anexemplary embodiment of the present inventive concept.

Referring to FIG. 9, the plasma processing system 100 a may includemagnetic coils 70 and a shutter plate 46 in a hollow cathode 40′. Thechamber 10, the gas supplying part 20, the electrostatic chuck 30, theelectron beam sources 50, and the confinement electrode 60 may beconfigured to have the same features as those of the previous examplesdescribed with reference to FIGS. 1 to 7.

The magnetic coils 70 may produce an electromagnetic field 78 in thechamber 10. The electromagnetic field 78 may deflect the electron beams52. For example, the electromagnetic field 78 may concentrate the upperplasma 102 from the edge region 16 toward the center region 14 ordisperse the upper plasma 102 from the center region 14 toward the edgeregion 16 of the chamber 10. (See also FIG. 7). The electromagneticfield 78 may also prevent the electron beams 52 from passing through thecathode holes 41. In the case where the electron beams 52 pass throughthe cathode holes 41, the substrate W may be damaged by the upper plasma102.

FIG. 11 illustrates exemplary magnetic coils 70 of FIG. 9 according tothe present inventive concept.

Referring to FIGS. 9 to 11, the magnetic coils 70 may include an innercoil 72 and outer coils 74.

The inner coil 72 may be provided in the confinement electrode 60. Whenviewed in a plan view, the inner coil 72 may be provided to have acircular shape. In addition, the inner coil 72 may define the centerregion 14 and the edge region 16 of the chamber 10. For example, thecenter region 14 may be defined as an inner region of the inner coil 72,whereas the edge region 16 may be defined as an outer region of theinner coil 72.

The inner coil 72 may be supported by a supporter 18, which is providedin the chamber 10. The supporter 18 may be a structure extending from anupper inner surface of the chamber 10, which is located between theelectron beam sources 50, toward an internal space of the confinementelectrode 60. The inner coil 72 may control differently an intensity ofthe electron beams 52 at the center region 14 of the chamber 10 and atthe edge region 16 of the chamber 10.

The inner coil 72 may induce an internal magnetic field 76 and aninternal electric field 77. The internal magnetic field 76 may beinduced along the inner coil 72 or in a circular shape. The internalelectric field 77 may be induced in a winding direction of the innercoil 72. Directions or intensities of the internal magnetic field 76 andthe internal electric field 77 may be controlled by the bias voltage Vof the confinement electrode 60. For example, in the case where the biasvoltage V is negative, the internal magnetic field 76 may be induced ina counterclockwise direction. The bias voltage V having a negative valuemay concentrate the electron beams 52 toward the center region 14 of thechamber 10 or the hollow cathode 40′. The velocity of the electron beams52 may be lower at the edge region 16 than at the center region 14. Theintensity of the internal magnetic field 76 in the chamber 10 may becomenon-uniform. The inner coil 72 may induce the internal magnetic field 76in the counterclockwise direction, and this may allow the electron beams52 to have uniform intensities at the center region 14 and the edgeregion 16 of the chamber 10 or the hollow cathode 40′. In the case wherethe inner coil 72 induces the internal magnetic field 76 in thecounterclockwise direction, the electron beams 52 in the inner coil 72may be decelerated by the internal electric field 77. The electron beams52 outside the inner coil 72 may be accelerated by the internal electricfield 77. Accordingly, it may be possible to improve uniformity inintensity of the electron beams 52 in the chamber 10. Nevertheless, thepresent inventive concept is not limited to thereto. In the case wherethe bias voltage V is positive, the internal magnetic field 76 may beinduced in a clockwise direction.

The outer coils 74 may be provided outside the chamber 10. For example,the outer coils 74 may be provided in side ports 11 of the chamber 10.The outer coils 74 may provide external magnetic fields 79 in thechamber 10. The external magnetic fields 79 may be provided in adirection perpendicular to the propagation direction of the electronbeams 52. If the propagation direction of the electron beams 52 isnormal to an upper surface of the dielectric plate 42, the externalmagnetic fields 79 may be provided in a direction parallel to the uppersurface of the dielectric plate 42. The external magnetic fields 79 maydeflect the electron beams 52. The external magnetic fields 79 mayprevent the electron beams 52 from being incident on the cathode holes41. The number of the outer coils 74 may be the same as that of theelectron beam sources 50. For example, twelve electron beam sources 50and twelve outer coils 74 may be provided. Although not shown, theexternal magnetic fields 79 may be provided to correspond to theelectron beams 52 in a one-to-one manner. The outer coils 74 may beconfigured to allow the external magnetic fields 79 to aim the electronbeams 52 individually.

Referring to FIG. 1 and FIGS. 7 to 11, the confinement electrode 60 maybe in the upper housing 10-UH of the chamber 10 to apply the biasvoltage V supplied from the voltage supplying unit 34 to control adeflection direction of the electron beams 52.

In an exemplary embodiment, the confinement electrode 60 a may includethe electrode sectors 62. The electrode sectors 62 of the confinementelectrode 60 a may be biased independently with the bias voltage V tocontrol the deflection direction of the electron beams 52.

In an exemplary embodiment, the inner coil 72 may be disposed in theupper housing 10-UH of the chamber 10 to generate the internal magneticfield 76.

In an exemplary embodiment, the inner coil 72 and the confinementelectrode 60 may be positioned at substantially the same height from anupper surface of the electrostatic chuck 30.

In an exemplary embodiment, the bias voltage V applied to theconfinement electrode 60 may control the internal magnetic field inintensity or direction. In an exemplary embodiment, the electron beamsources 50 may include the first electron beam sources 50A overlappedwith an inner region of the inner coil 72, and the second electron beamsources 50B overlapped with an outer region of the inner coil 72.

The outer coils 74 may be attached to the chamber 10 to provide theexternal magnetic fields 79 to the upper plasma 102 in a directioncrossing the traveling direction of the electron beams 52. Referring toFIGS. 9 and 10, the hollow cathode 40′ may include the shutter plate 46.The dielectric plate 42 a of the hollow cathode 40′ may have a gap 38between the lower electrodes 43 and the upper electrodes 45. The shutterplate 46 may be provided in the gap 38. The dielectric plate 42 a mayinclude an upper plate 42 a-UP surrounding the upper electrodes 45, alower plate 42 a-LP surrounding the lower electrodes 43 and a connectingplate 42 a-CP connecting an end of the upper plate 42 a-UP and an end ofthe lower plate 42 a-LP. The upper plate 42 a-UP, the lower plate 42a-LP and the connecting plate 42 a-CP may define the gap 38 of thedielectric plate 42 a to receive the shutter plate 46.

However, the present inventive concept is not limited thereto. Forexample, the connecting plate 42 a-CP may be omitted so that thedielectric plate 42 a may include a lower plate and an upper plate only,and the shutter plate 46 may be provided between the lower plate and theupper plate of the dielectric plate 42 a.

FIGS. 12 and 13 are plan views showing a change in open state of thecathode holes 41 of the dielectric plate 42 a, which occurs when theshutter plate 46 of FIGS. 9 and 10 is rotated, according to an exemplaryembodiment of the present inventive concept.

Referring to FIGS. 9, 10, 12, and 13, the shutter plate 46 may beconfigured to move or rotate in the gap 38. In some embodiments, theshutter plate 46 may have shutter holes 47. The shutter holes 47 may bealigned to the cathode holes 41. The shutter holes 47 may havesubstantially the same diameter as that of the cathode holes 41.

Referring to FIGS. 9 and 12, if the cathode holes 41 are aligned to theshutter holes 47, the lower plasma 104 may be generated in the cathodeholes 41 and the shutter holes 47. In some embodiments, physicalproperties (e.g., energy or intensity) of the lower plasma 104 may bechanged to control a ratio of ions to radicals, produced from thereaction gas 22, in the reaction plasma 106. If the intensity of thelower plasma 104 is increased, the number or density of the ions may belarger than that of the radicals in the reaction plasma 106. The ratioof the ions to the radicals may be increased. If the intensity of thelower plasma 104 is decreased, the number or density of the ions may beless than that of the radicals in the reaction plasma 106. The ratio ofthe ions to the radicals may be decreased.

Referring to FIGS. 10 and 13, the shutter plate 46 may be rotated in thegap 38, thereby closing the cathode holes 41. The shutter holes 47 andthe cathode holes 41 may be off-centered with respect to each other. Inthis case, the shutter plate 46 may shut off the reaction gas 22. Thelower plasma 104 of FIG. 9 may be removed.

The plasma processing system may be used in a process of fabricating asemiconductor device, as will be described below.

FIG. 14 is a flow chart illustrating a method of fabricating asemiconductor device, according to an exemplary embodiment of thepresent inventive concept.

Referring to FIG. 14, a method of fabricating a semiconductor device mayinclude supplying the reaction gas 22 (in S10), inducing the upperplasma 102 (in S20), aligning the shutter holes 47 to the cathode holes41 (in S30), and inducing the lower plasma 104 (in S40).

Referring to FIGS. 1, 9, and 14, if the substrate W is loaded on theelectrostatic chuck 30, the reaction gas 22 in the gas supplying part 20may be supplied into the upper housing 10-UH of the chamber 10 locatedon the hollow cathode 40 (in S10). The reaction gas 22 may be or includean etching gas, a deposition gas, an inert gas, or a purge gas.

Thereafter, the electron beams 52 from the electron beam sources 50 maygenerate the upper plasma 102 (in S20). In an exemplary embodiment, thegenerating of the upper plasma 102 (in S20) may include providing theelectron beams 52 (in S22), concentrating the electron beams 52 (inS24), providing the internal magnetic field 76 (in S26), and providingthe external magnetic field 79 (in S28).

The electron beam sources 50 may provide the electron beams 52 in adirection perpendicular to the hollow cathode 40 (in S22). The electronbeams 52 may produce the upper plasma 102 from the reaction gas 22.

The confinement electrode 60 may concentrate the electron beams 52within the center region 14 of the chamber 10 or the hollow cathode 40using the bias voltage V (in S24). For example, the substrate W may beprovided in the center region 14 of the chamber 10 or the hollow cathode40. If the bias voltage V is negative, the electron beams 52 may beconcentrated near the center region 14. By contrast, if the bias voltageV is positive, the electron beams 52 may be concentrated near the edgeregion 16 of the chamber 10 or the hollow cathode 40.

The inner coil 72 may exert the internal magnetic field 76 on theelectron beams 52 to uniformly control the intensity of the electronbeams 52 (in S26). The internal magnetic field 76 may cause a differencein intensity of the electron beams 52 at the edge region 16 and at thecenter region 14 of the chamber 10 or the hollow cathode 40. Theelectron beams 52 may be accelerated at the edge region 16 and may bedecelerated at the center region 14.

The outer coils 74 may exert the external magnetic fields 79 on theelectron beams 52 to prevent the electron beams 52 from passing throughthe cathode holes 41 (in S28). The external magnetic fields 79 may beprovided in a direction parallel to the dielectric plate 42 a of thehollow cathode 40. The external magnetic fields 79 may be provided tocorrespond to the cathode holes 41 in a one-to-one manner. The externalmagnetic fields 79 may be used to deflect the electron beams 52 on thecathode holes 41. The electron beams 52 may be deflected by the externalmagnetic fields 79. By contrast, the electron beams 52 may beextinguished in the cathode holes 41 by the external magnetic fields 79.

Next, the shutter holes 47 of the shutter plate 46 may be aligned to thecathode holes 41 by a controller (not shown) or an operator (in S30).The reaction gas 22 in the cathode holes 41 and the shutter holes 47 maybe provided in the cathode holes 41 and the shutter holes 47.

An RF power may be applied to the reaction gas 22 through the upperelectrode 45, thereby generating the lower plasma 104 in the shutterholes 47 and the cathode holes 41 (in S40). A ground voltage may besupplied to the lower electrodes 43. The intensity of the lower plasma104 may be dependent on the RF power.

When an etching process is performed on the substrate W, the ratio ofthe ions to the radicals, which are produced from the reaction gas 22,in the reaction plasma 106 of FIG. 1 may be changed depending on the RFpower. The ions of the reaction gas 22 may serve to increase an etchrate of the substrate W. However, the ions of the reaction gas 22 maylead to damage of the substrate W. Thus, to suppress or prevent suchdamage of the substrate W, the RF power may be controlled by acontroller (not shown) or the first power supplying unit 32. Thereaction plasma may be supplied to the wafer to perform an etchingprocess on the wafer.

In an exemplary embodiment, an etching profile of the wafer caused bythe etching process may depend on the predetermined ratio of the ions tothe radicals of the reaction plasma 106 of FIG. 1, for example. If thepredetermined ratio of the ions to the radicals of the reaction plasmaincreases, the etching process may cause the etching profile of thewafer to be more anisotropic; and if the predetermined ratio of the ionsto the radicals of the reaction plasma 106 decreases, the etchingprocess may cause the etching profile of the wafer to be more isotropic.

FIG. 15 is a diagram illustrating a semiconductor fabricating system 300including the plasma processing system 100 of FIG. 1 according to anexemplary embodiment of the present inventive concept.

Referring to FIG. 15, the semiconductor fabricating system 300 mayinclude a lithography system 200 and the plasma processing system 100.The lithography system 200 may be configured to form a resist pattern(not shown) on the substrate W. The lithography system 200 may include,for example, a spin coater, a baker, a scanner, and a developer. Theplasma processing system 100 may etch portions of the substrate Wexposed by the resist pattern. In an exemplary embodiment, the plasmaprocessing system 100 may deposit a thin film on the substrate W, beforea lithography process using the lithography system 200.

According to an exemplary embodiment of the present inventive concept, aplasma processing system may induce an upper plasma and a lower plasmafrom a reaction gas. The upper plasma may be induced by an electronbeam. Physical properties (e.g., energy or intensity) of the lowerplasma may be changed to control a ratio of ions to radicals, which areproduced from the reaction gas in a reaction plasma remotely formed fromthe upper plasma and the lower plasma.

While the present inventive concept has been shown and described withreference to exemplary embodiments thereof, it will be apparent to thoseof ordinary skill in the art that various changes in form and detail maybe made therein without departing from the spirit and scope of theinventive concept as defined by the following claims.

What claimed is:
 1. A plasma processing system, comprising: a chamberhaving an upper housing and a lower housing and receiving a reactiongas; a first plasma source including a plurality of electron beamsources that provide a plurality of electron beams into the upperhousing of the chamber to generate an upper plasma from the reactiongas; a second plasma source including a plurality of holes that areconfigured to generate a lower plasma from the reaction gas within theplurality of holes connecting the upper housing and the lower housing,wherein radicals of the upper plasma, radicals of the lower plasma, andions of the lower plasma are provided, through the plurality of holes,to the lower housing so that the lower housing has radicals and ions ata predetermined ratio of the ions of the lower housing to the radicalsof the lower housing in concentration, and wherein the second plasmasource divides the chamber into the upper housing and the lower housing;and a wafer chuck positioned in the lower housing to receive a wafer. 2.The plasma processing system of claim 1, wherein the second plasmasource is configured to block ions of the upper plasma from beingprovided into the lower housing through the plurality of holes.
 3. Theplasma processing system of claim 1, wherein the second plasma sourcefurther includes a first RF power providing an RF power to the reactiongas within the plurality of holes to adjust the predetermined ratio ofthe ions of the lower housing to the radicals of the lower housing. 4.The plasma processing system of claim 3, wherein the second plasmasource further includes an upper electrode, a lower electrode and adielectric plate surrounding the upper electrode and the lowerelectrode, wherein the first RF power is coupled to the upper electrodeand a ground voltage is coupled to the lower electrode so that thedielectric plate has a positive DC bias to block ions of the upperplasma from being provided into the lower housing through the pluralityof holes.
 5. The plasma processing system of claim 4, wherein thedielectric plate of the second plasma source is formed of an insulatingmaterial.
 6. The plasma processing system of claim 4, furthercomprising: a shutter plate interposed between the upper electrode andthe lower electrode, wherein the shutter plate includes a plurality ofshutter holes, and wherein the shutter plate is configured to rotate sothat the plurality of shutter holes are aligned to the plurality ofholes so that the radicals of the upper plasma are provided, through theplurality of holes, to the lower housing.
 7. The plasma processingsystem of claim 6, wherein the dielectric plate includes an upper platesurrounding the upper electrode, a lower plate surrounding the lowerelectrode and a connecting plate connecting an end of the upper plate toan end of the lower plate, and wherein the upper plate, the lower plateand connecting plate define a gap of the dielectric plate to receive theshutter plate.
 8. The plasma processing system of claim 3, wherein thefirst RF power provides an RF power of which frequency ranges from about1 KHz to about 100 MHz.
 9. The plasma processing system of claim 1,wherein the plurality of electron beam sources include a plurality offirst electron beam sources and a plurality of second electron beamsources, wherein the plurality of first electron beam sources aredisposed within a perimeter of the wafer if placed on the wafer chuck,and wherein the plurality of second electron beam sources overlap theperimeter of the wafer if placed on the wafer chuck or are disposedoutside of the perimeter of the wafer if placed on the wafer chuck. 10.The plasma processing system of claim 9, wherein a number of theplurality of first electron beam sources is smaller than a number of theplurality of second electron beam sources.
 11. The plasma processingsystem of claim 9, wherein the plurality of first electron beam sourcesare equally positioned from a center of the wafer chuck.
 12. The plasmaprocessing system of claim 1, wherein each of the plurality of electronbeam sources comprises: a source housing having a hollow inside and anopening and receiving a source gas; a second RF power generating asource plasma in the hollow inside of the source housing, the sourceplasma having a plurality of electrons; and a source electrode having anaperture allowing the plurality of electrons to pass from the sourceplasma in the hollow inside of the source housing to the upper housingof the chamber.
 13. The plasma processing system of claim 12, whereineach of the plurality of electron beam sources further comprises: asource coil attached to an outer circumference surface of the sourcehousing.
 14. The plasma processing system of claim 1, furthercomprising: a confinement electrode in the upper housing of the chamber,wherein a bias voltage is supplied to the confinement electrode tocontrol a deflection direction of each of the plurality of electronbeams.
 15. The plasma processing system of claim 14, wherein theconfinement electrode is of a circular shape, and wherein theconfinement electrode includes a plurality of electrode sectors.
 16. Theplasma processing system of claim 15, wherein the bias voltage issupplied independently to the plurality of electrode sectors of theconfinement electrode to control independently the deflection directionof each of the plurality of electron beams.
 17. The plasma processingsystem of claim 14, further comprising: an inner coil disposed in theupper housing of the chamber to generate an internal magnetic field,wherein the inner coil and the confinement electrode are positioned atsubstantially the same height from an upper surface of the wafer chuck.18. The plasma processing system of claim 17, wherein the bias voltageapplied to the confinement electrode controls the internal magneticfield in intensity or direction.
 19. The plasma processing system ofclaim 17, wherein the plurality of electron beam sources include aplurality of a first electron beam sources disposed within an innerregion of the inner coil, and a plurality of a second electron beamsources disposed within an outer region of the inner coil.
 20. Theplasma processing system of claim 17, further comprising: a plurality ofouter coils attached to the chamber and configured to provide aplurality of external magnetic fields to the upper plasma in a directioncrossing a traveling direction of the plurality of electron beams.